Fluid fuel burning floor furnace



4 328 6 MMGGG a7 Hap 7/'45 HRM Arrow/E Ys 2 Sheets-Sheet l [N VEN Tol? JAMES SMNLEYJOHNSON s, K/EcH, F2575@ dc Hnm/s v May 17, 1949. J. s. JOHNSON 4 V FLUID FUEL BURNING FLOOR FURNACE Filed Aug. 28, 1944 4 lIIllll lll llll

By' HARR/ May 17, 1949. J. s. JoHNsoN FLUID FUEL BURNING FLOOR FURNACE vNm .o o .aM/w MH MN Oumme @Je m OYE .fr Tfr r NM@ MAF Nrw [5x am,

3 tion showing an alternative pilot-guiding structure;

Figure '7 is a top view, partially in section, of an alternative pilot construction; and

Figure 8 is a vertical sectional view, taken along the line 8-8 of Figure 7.

Referring particularly to Figures 1 to 5, the exemplified floor furnace includes a generally rectangular outer casing i having a bottom wall Il and of such dimensions as to be inserted in an opening I2 of the floor. The length of the outer casing is such as to occupy the space between two members such as joists I3 supporting rough flooring i4 and finished flooring i5, or the members i3 may be opposed members of a framed-in opening. The outer casing it may be suspended in an opening i2 by any conventional means and extends downwardly beneath the floor to occupy a portion of the space above the ground level. The opening I2 is later covered by the usual grill I6.

A combustion-chamber structure 2li is disposed within the outer casing Il! to form a circulating-air passage, indicated generally by the numeral 2l, between the outer casing Il! and the exposed surfaces of the combustion-chamber structure 20. It is often desirable to provide a rectangular inner casing 22 as a baille means in the circulating-air passage 2|. As shown, this inner casing 22 is a double-walled structure including inner and outer rectangular baies 24 and 25 with an air-filled insulating space therebetween open at its top and bottom. It should be understood, however, that a single-walled inner casing can be employed. In operation, cool air drawn from the room moves downwardly in the outer portion of the circulating-air passage 2l between the outer casing i6 and the outer baille 25, as indicated by arrow 21, flowing thence under and upward within the inner casing 22, as suggested by arrows 28, to be heated by indirect heat transfer from the products of combustion in the combustion-chamber structure 26. If desired, additional air may enter from beneath the floor through an opening 36, shown in Figure 2, but the use of such an opening is optional.

The lowerrnost end of the combustion-chamber structure is open and is aligned with, and preferably extends snugly into, a rectangular opening 32 of the bottom wall Il. This combustion-chamber structure 20 provides a `combustion chamber 33 open at its lower end to receive an elongated burner 35 disposed below or within the open lower end. The products of combustion move upward and through lateral ues 36 toa vertical ue 31, and thence downward to a lateral ue 3S which terminates in or just beyond a recessed portion 39 of the side wall of the outer casing l0, as best shown in Figure 2, to provide a collar lil adapted to receive a suitable vent 'connection extending to an upright vent or flue leading to the top of the building.

,The combustion-chamber structure 20, which may be considered as comprising the combustion chamber and the flues 36 and 31, thus confines the hot products `of combustion which, before being withdrawn by the ue 38 traversing the circulating-air passage 2l, heat the internal structure to transfer heat to the circulating air.

It is often desirable to mount a pan l5 at the bottom of the unit to protect the burner against drafts and for other purposes. As best shown in Figures 1 and 2,'this pan t5 need extend only beneath the burner and can be of less width and length than the outer casing I0. One end thereof is open to provide an air inlet opening 46. This pan is removably connected to the outer casing as indicated by the numerals 41 and 48.

Prior to installation of the oor furnace, the rough plumbing will have been installed, including a fuel-supply pipe 5l) shown as extending through one of the members or joists I3 and being stubbed off immediately therebeyond. As the extremity of this fuel-supply pipe extends into the opening I2 which is to receive the floor furnace and as it is in the path of movement of an end Iwall 54 of the outer casing I6, it is desirable to provide an upright passageway 52 extending vertically along this end wall of the outer casing i6. This passageway is formed by a covered or uncovered vertical slot open at its lower` end and extending upward a distance to accommodate the fuel-supply pipe during lowering oi the casing. In the preferred embodiment, this passageway is formed, and the slot is covered, by a U-shaped structure 53 extending inwardly of the outer casing Hi. This U-shaped structure 53 may be formed as a separate element connected to the end wall 54 of the outer casing I0, in which event it will, in effect, bridge the vertical slot of this end wall, or it may be formed integrally with the end wall 54, as by deforming same to provide the U-shaped structure 53 as a vertical channel to bound the outwardly-opening passageway 52. The lower most end of the U-shaped structure 53 terminates at the bottom wall Il, as best shown in Figure 5, while the upper end, indicated by the numeral 55, terminates just below the fuel-supply pipe 50 when the furnace is in installed position. The upper end of the slot in the end wall 54 is above the upper end 55 of the U-shaped structure 53 to provide an opening 56 loosely receiving the end of the fuel-supply pipe. Thus, the stubbed-o' pipe 5B does not interfere with the downward movement of the furnace during installation, and the upper end 55 of the U- shaped structure 53 terminates a suflicient distance below the pipe 50 to permit unscrewing any pipe cap previously thereon and substituting an elbow 51.

The fuel-control means of the furnace is preferably positioned sufficiently near the upper end of the outer casing l0 to be accessible through the open' top thereof for connection, inspection, or repair. This fuel-control means may include a pressure regulator 60, a pilot-control valve 6I, and a main or burner-control valve 62 best shown in Figures 3 and 4, or other fuel-control devices. The main valve 62 is Shown as being manually controlled by insertion of a suitable key through the grill i6 to engage a stem 63 of the valve, but it should be clear that a thermostatically-controlled main valve may be substituted or employed in addition to the main valve. As illustrated, the pressure regulator 60 and the valves 6I and 62 are connected to the elbow 51 by a suitable coupling 58, preferably a exible copper pipe secured to the elbow 51 and a nipple of the pressure regulator 6E) by internally threaded hexagonal collars 66, or a suitable pipe union may be employed.

In the preferred embodiment of the invention, fuel-conducting pipe means extends downwardly from the fuel-control means at a position just inside one end of the outer casing I0, as best shown in Figures 1, 3, 4, and 5. This pipe means includes a main burner-supply pipe 65 extending downwardly through a pipe-conducting open- 5 ing 56 of the bottom wall H and thence inwardly to an air mixer 6T of the burner 35.

The fuel-conducting pipe means includes also a small pilot-supply pipe 68, usually formed of one-quarter inch copper tubing to be readily ben-t, this pipe extending through the pipe-conducting opening 6B and the lower end of the pipe providing a lower pilot-connectedportion 69 to which a pilot 1D is connected. This pilot has the usual 'oriiiced head and is disposed to produce a burnerlghting llame in the combustion chamber. In this embodimentr of the invention, the pilot or pilot flame enters the combustion chamber sidewise through a pilot-receiving opening l2 separ- `rate from the burner-receiving opening, namely, the open lower end of the 'combustion chamber 33. The uppermost end of the pilot-supply 68 is removably connected to the phot-control valve Si, preferably by' use of a detachable fitting 13,

for example a flared fitting in which a hexagonal f collar threaded to the pilot-control valve et draws the pilot-supply pipe 68 against the valve. By use of this type of tting, the entire pilotassembly (including the pilot-supply pipe 58, the pilot-connected portion 69, and the pilot 1U), can be attached or detached from the pilot-control valve 6| merely by turning the hexagonal collar, thus permitting attachment or detachment of the pilot assembly without unscrewing the whole pilot assembly from the pilot-control valve. However, ff

a screw-type tting can be employed if desired. The amount of fuel supplied to the pilot is controlled by turning a valve stem lli, engageable by a key inserted through the grill It.

The invention contemplates that the lower pilot-connected portion 69 be movable and, in this embodiment of the invention, sidewise movement thereof is possible by manual flexure of the upper portion of the pilot-supply pipe 68, even when connected to the valve Bl by the fitting 13, access being had through the open top of the oufter casing Hl. By manual flexure of the pilotsupply pipe 68 to move the lower end toward the end wall of the casing l0, the lower pilot-connected portion 69 can be made to swing outward, while substantially horizontally disposed,l from its position shown in Figure l. Alternatively, if the iitting 13 is disconnected, thev lower pilotconnected portion G9 `can be moved horizontally outward from the vicinity of the pilot-receiving opening T2, and the entire pilot assembly can be 4removed by access through the open top of the outer casing |20;

In addition, the preferred embodiment of the invention preferably provides a guide means for receiving the pilot 10 and the pilot-connected portion 69 toi guide same into correct burnerligllting relationship, While at the same time facilitating the installation and removal of the pilot assembly as a whole. For this purpose, Figures l and 2 illustrate a pilot guide l5 providing a plint-guiding passage 16 below the bottom wall l t.. This pilot guide is preierably tubular and is shown in Figure 2 ats-comprising a U-shaped member secured to the bottom wall I I. In this embodiment, the outermost end of the pilot guide l5 terminates short oi the pipe-conducting opening 65, preferably at the inner end of a pilot-receiving opening or slot l1, which opens on the pipe-conducting opening 661, as best shown in Figure 3. The

.pilot-receivmg opening or slfot 'Fl is preferably closed: by a removable cover i8, mounted' as will *bev later described. Generally stated, the outermost end of the pilot guide 'F5 should termin-ate short or the. outercasing l il, preferably aft a point,

usually below'the inner casing 7.2, which will per mit withdrawal of the pilot 'wand the pilot-connected portion 69 from the pilot guide in a manner to be'hereinafter described.

It isY usually desirable to enclose the fuel-con.- ducting pipe means from the air circulating in the circulating-air passage 2 l'. For this and other purposes, the invention provides a wall structure Ml, pret'eralilyl removable. In the preferred embodiment shown in Figures l to 5, this wall structure includes a U-shaped partition wall 8l' forming a space 82 immediately inside an end wall of ythe outer casing I 0. The side members of the partition wall 8i may be detachably` connected t0 this end wall of the casing by any suitable means. For exampley each side member may include an outwardly-bent tongue 83 vertically movable in a guide- 8-4 secured to the casing, whereby the entire partition wall is vertically slidable from the casing HiV through the open top thereof. The lowerm-ost end of the'partition wall 3l rests flush against the bottom wall H at the periphery of the pipe-conducting opening 66, andthe cover 'F8 for the pilot-receiving opening or slot Tl is preferably connected to the lower end ofthe partition wall so that this opening or slot is automatically closed off when the partition wall is loweredy into the position shown in Figure l. The uppermost end of the partition wall 8| preferably carries a cover 35 for closing the upper end of the space 82, this cover terminating flush with the inner surface of the end wall of the outer casing I 0; An opening lBil (Figure Lilmay be provided for snugly receiving the stem 63 of the main valve, and another opening 8l above the pilot-control valve 6l for receiving the 'stem 14' of the pilot valve'. The width of the partition wall 8l between its side members is preferably, though not I necessarily, less than the width of the outer v"40 casing lll, whereby this partition wall occupies only a portion of the circulating-air passage 2t at this end of the heating unit.

In installing the heating uni-t thus far described, the entire assembled unit is lowered n the opening l2, the outwardly-facing passage- Way 52 accommodating. the stubbed-oilfuel-supply pipe Eil. as previously described. The partition Wall 8| will lbe removed during installation and the pressure regulator 60, valves 6l and 62, and main burner-'supply pipe 65 may be sequentially connected to Ythe fuel-supply pipe 50. Alterna- `tively and preferably, ythese elements may previously have been assembled and mounted securely in the Outer casing l0, the complete pipe assemblyr being then connected? to the elbow 5T, after lowering the heating unit, by the ilexible tubing connector or coupling 63. The pilot assembly can form a part of this pipe assembly, having previouslyV been positioned in 4the pilot guide, or' this pilot assembly may subsequently be lowered through the pipe-conducting opening 66 and the pilot-receiving slot 1T being then moved inwardly so that the pilot T0" is within the pilot vguide 15, this guide insuring correct guidance into burner-lightingrelationship. The uppermost end 'of the pilot-supply pipe Ell will then be connected by fitting-'I3 to the pilot-control valve 6l. Any necessary adjust-ments of the fuel-controlV means are then mad-e', after which the partition wall 81 is lowered into position.

In removing the pilot assembly for inspection or repairs, the partition wall 8f is lfirst removed. The hand can then be insertedk into the open top ofthe casing l0 and the pilot-suppiy'pipe 68 deformed toward the outer casing f, thus swing- :top of the outer casing I0.

ing the pilot out of the pilot guide 15. At this time, the pilot-supply pipe 68 can be further bent to bring the pilot toward the top of the outer casing while still connected to the pilot-control valve 6I, this being possible in view of the flexible nature of the pipe 68. Inspection or repairs can be made and the pilot reinserted into the pilot guide 15. Alternatively, the coupling 13 can be disconnected and the pilot 10 swung outward and thence upward through the slot 'l1 or opening 66 for inspection or repairs.

In the alternative construction suggested in Figure 6, the pilot-receiving opening, indicated by 12a, is disposed above the bottom wall Il, as is also. the pilot guide 15a. In this instance, this pilot guide is suitably secured to the outer wall of the combustion-chamber structure to prevent any possibility of leakage of fuel or products of combustion into the circulating-air passage 2l. In this embodiment, a pilot-receiving opening or slot 11a is formed in the lower end of the partition wall 8|, and a removable cover 18a, preferably secured to the partition wall, encloses the pilot-supply piping from the circulating-air passage and preferably extends downwardly snugly around the pilot guide 15a. It will thus be apparent that the pilot guide can be above or below the bottom wall Il of the heating unit.

The invention contemplates the employment of any means for inserting and removing the pilot assembly from the open top of the casing. An alternative construction, permitting hinged or lateral swinging of the pilot into and from its burner-lighting relationship, is shown in Figures '7 and 8. Here, the pilot-supply pipe 68 and the pilot-connected portion 69 are adapted to swing about a vertical axis in the space 82 and passing through the pilot-control valve 6|. The pilotconnected portion S9 is bent inwardly so that the pilot 'lli swings into and from an opening |00 in a side wall of the combustion-chamber structure 20, as best .shown in Figure 7. The pilot may be guided by a flaring pilot guide IUI secured to the combustion-chamber structure. To remove the pilot structure of this embodiment of the invention, it is necessary only to loosen the fitting 13 and, by grasping the pilot-supply pipe 63, turn it into dotted line position IM of Figure 7 for inspection. If repairs are desired, the fitting 'I3 is completely removed, whereupon the entire pilot structure can be drawn upward through the space 82.

It will be apparent that the pilot guide 15 or IUI facilitates correct insertion of the pilot which can enter such pilot guide at a position removed from the combustion chamber and be guided into and retained in correct burner-lighting position. It will be apparent, also, that all embodiments of the invention herein-suggested provide for movement of the pilot in a substantially horizontal direction toward and away from the combustion chamber by manual access through the open In fact, all of the elements of a heating unit likely to give trouble or difcult to service are positioned near, and insertable or removable from, the upper end of the casing, being accessible from the room and lthus requiring no entry into the restricted space between the floor and the ground.

The embodiments of the invention hereindisclosed are merely exemplary. While I have chosen to illustrate the invention as applicable to a floor furnace, it should be apparent that it can be used also with licor-installed space heaters or other heating units, in which, for example, the bottom wall Il is eliminated and in which, for example, the partition 8| can sometimes be eliminated. It will be apparent, also, that various changes and modifications can be made without departing from the spirit of the invention as defined in the appended claims.

I claim as my invention:

l. In a heating unit for installation in the floor of a building, said floor being disposed a -distance above the ground sufficient to receive the heating unit when lowered through an opening of the floor, said heating unit including in combination: an outer casing having an open top and ladapted for suspension in said opening to be disposed below said floor; a combustion-chamber structure fixed within said outer casing and spaced therefrom to define a circulating-air passage, said combustion-chamber structure defining a combustion chamber; a burner for burning fuel in said combustion chamber; means for conducting products of combustion from said combustion chamber; fuel-control means disposed within said outer casing below floor level but near the upper end of said outer casing to be accessible through the open top of said casing, said burner being located below said fuel-control means; a fuel-conducting pipe extending downwardly from said fuel-control means to said burner; a pilot extending into said combustion chamber, said pilot being disposed below said fuel-control means; a pipe means including a pilot-connected portion extending to and communicating with said pilot to supply fuel there- ,$5 to, said pipe means including an upwardly-extending portion; and wall means within the outer confines of said outer casing and providing an upright space separated by said wall means from said circulating-air passage, said pipe means extending downwardly in said upright space.

2. A combination as defined in claim l, including a pilot-control valve within said outer casing near the upper end thereof to be accessible through the open top of said casing, and including means for detachably connecting said upwardly-extending portion of said pipe means to said pilot-control valve, said upwardly-extending portion being accessible through the open top of said outer casing to permit removal of said pipe means therethrough.

3. A combination as defined in claim 1 in which said fuel-control means is disposed in the upper end of said upright space and in which said fuelconducting pipe extends downwardly in said space.

4. A combination as defined in claim 1 in which said wall means includes a partition wall and means for removably connecting same to said outer casing.

5. A combination as dened in claim l in which said wall means includes a partition wall having side portions, and including means for slidably connecting said side portions to said outer casing to permit said partition wall to be removed from said circulating-air passage.

6. In a heating unit for installation in the floor of a building, said floor being disposed a distance above the ground suilcient to receive the heating unit when lowered through an opening of the floor, said heating unit including in combination: an outer casing having an open top and adapted for suspension in said opening to be disposed below said floor, said outer casing providing a wall; a combustion-chamber structure within said outer casing and spaced there:-

irai-n -to denne a circulating-air passage, .-said rcomloustion-.chambier structure dening a combustion chamber; fa burner for fb-,urning liuel .in `said :combustion fchamber; fmeans for vconducting products -of combustion .from vsaid combustion cha-mbar; :a `fuel-conducting 1pipe means providan upper end adapted for connection yto a .source -of `fuel fand extending `.downwardly Vinside ,said -outer casing at a -location spaced from said @Wall of such casing, said lfidel-conducting pipe means :supplying vifuel to said :bur-ner; ,and a parftition wall extending across Asaid yfuel-conducting pipe and :having `ends V`extending to said wall ,at xopposite sides lof rsaid yhiel-.conducting pipe -means A,to :for-m a space separated by said partition wall from the y.air circulating in said ycirculating-air passage, the distance .between said .ends vof said partition wall .being less than the horizontal length of said first-named wall.

7. y.A combination .as dciined inclaim 6, .including means for .detachably connecting said .par-

tition -wall to said wall of Vsaid casing to permit removal of s aid .partition wall by access through the open vtop of said casing to .give access to said fuel-conducting pipe means.

8. Ina heating unit for 4installation in the floor of a building, said Afloor being disposecla distance above 'the ground su'iicient lto receive the heating unit when lowered through an opening of the lioor, 'said heating unit including 'in combination: an outer casing having an open top and adapted for k.suspension 'in said opening to be disposed beiow Vsaid floor, said outer casing having a lower wall providing -an opening; a combustion-chamber structure extending vupwardly from said opening of said #lower wall and spaced from said outer casing to define a circulating-air passage; a burner disposed a-t lleast partially below Said wall for burning Yfuel within said combustion-'chain- -ber structure; means for conducting products of combustion from said combustion-chamber Vstructure; fuel-conducting `pipe means exten-ding downwardly Within said outer Jcasing, said lower wall providing Ia pipe-conductingopening through which said pipe means extends to said burner; and Wall means extend-ing from said pipeeconducting opening of said lower wall to a position above the upper end of said fuel-conducting pipe means providing a space for said pipe means, said wall means .separating said space from air circulating in said vcirculating-air passa-ge, said fuel-conducting pipe means extending down- Wardly in said space.

9. A combination .as :dened in-claim 8, in which said pipe means includes a small pilot-supply pipe extending downward in said space and providing a lower portion extending sidewise toward .said

. combustion chamber, and including va vpilot foarried .by said lower portion, said lower wall providing a pilot-removing opening between said pipe-conducting opening and said combustionchamber structure of sufficient size to pass said pilot and said loWer portion of said `pilot pipe, yand including a removable cover for said pilot-receiving opening.

l0. In a heating unit for installationin the floor of a building, said floor being disposed a distance above the ground sufcient to receive the heating unit when lowered through an opening of the floor, said heating unit including in combination: a-n outer casing having an open top and adapted for suspension in said opening from sai-d floor; a combustion-chamber structure Within said outer casing and spaced therefrom to define a vcirculating-air passage, said Ycombustion-chamber structure defining fa .conibustion chamber and having a .burner-receiving opening and -a separate pilot-receiving opening disposed vabove the burner-.receiving opening; a 'burner adjacent said burner-receiving opening; means for y,conducting products .of .combustion from said v:combustion chamber; va ,pilot .extending substantially .horizontally through .said pilot receiving opening; and means Ifor .mounting :said I,pilot .to .swing into and dfrom said pilot-receiving opening.

:11. A vcombination vas deined in claim l0, Ain which said burner-receiving.opening vis .at the bottom of said combustion-.chamber structure, .and in which .this .structure provides a substantially vertical wall -in which is formedsaid pilot-receivfingopening.

12. In .a heating unit for installation .in lthe door of a :.building, said .door being disposed :a distance .above the ground sucient :to receive .the heating unit when lowered through an .opening of .the floor., said 'heating unit including in combination: an outer casing having an .open top .and adapted for suspension in said opening to be disposed belowsaid floor; acombustion-cham7 ber structure within said outer .casing and spaced therefrom to define a circulatingair passage; a burner for burning .fuel in said combustion-chamber structure; a partition wall mounted in said outer casing and cooperating therewith dei-lning `a vertically-extending .space substantially closed from communication with air .moving jin said circulating-air passage; va pilot valve in said space .at a position Ato befmanually accessible through sai-d open vtop of said casing; a pilot fassembly including .a Ipilot and apilot-.supply pipe extending downward through said space rand providing a pilot-carrying portion attached to said pilot, said .pilot-.carrying portionpxtending -inwardly a su'mcient distance to disposel said pilot in .burner-lighting relationship; andfpieans near said .open `.top yof said .casing for -detaphably aconnecting said pilot-supply pipe to said pilot valve, said space being of sufficient horizontal dimension .to permit removal of said pilot assembly :by dra-wing same upward through said space after disconnection yfrom said pilot valve.

13. In a heating unit for installation Ain the door of a building, said ,floor being disposed a distance above the ground -suicient to receive the heating unit when lowered through an opening of the door, said heating unit including combination: -an outer casing having an open top and adapted for suspension in said opening to :be disposed below said floor; a combustion-chamber structure within said outer casing and spaced therefrom to define 'a circulating-air passage, said combustion-chamber struc-ture defining a coinbustion chamber and providing aside Wall have ing a pilot-receiving opening; a burner for burning fue-l in said combustion chamber; means .for conducting products of combustion from .said combustion chamber; a pilot tor producing -a burner-lighting flame in .said .combustion chamber; and a movable pilot-supply pipe providing a downwardly-extending portion extending downs wardly inside said outer casing from va point near the top ci" said Vcasing and manually movable 'by access through the open top thereof, said pilote supply pipe also providing a lower pilot-con nected portion extending sidewise from said downwardly-extending portion and lcarrying said pil-ot in position to swing substantially horizonV tally into and from said pilot-receiving opening- 11 when the upper end of said downwardly-extending portion is moved.

14. A combination as defined in claim 13, including guide means adjacent said combustionchamber structure and communicating with said pilot-receiving opening for guiding said pilot toward and away from said pilot-receiving opening when swinging into and from said opening.

15. In a heating unit for installation in the iioor of a building, said oor being disposed a distance above the ground suicient to receive the heating unit when lowered through an opening of the floor, said heating unit including in combination: an outer casing having an open top and adapted for suspension in said opening to be disposed below said floor; a combustion-chamber structure within said outer casing and spaced therefrom to dene a circulating-air passage, said combustion-chamber structure deiining a combustion chamber; a burner for burning fuel in said combustion chamber; means for conducting products of combustion from said combustion chamber; a pilot for producing a burner-lighting iiame in said combustion chamber; a, pilot-supply pipe extending downwardly inside said outer casing from a point near the top of said casing and accessible through the open top thereof, said pilot-supply pipe providing a lower pilot-connected portion extending sidewise to said pilot;

and walls defining a. pilot-guiding passage extending away from said combustion-chamber structure to receive said pilot and said lower pilotconnected portion and guide sai-d pilot into and from said combustion chamber, said lower pilotconnected portion being displaceable substantially horizontally to withdraw said pilot from said combustion chamber through said pilotguiding passage by manual movement of the downwardly-extending portion of said pilot-supply pipa-f 16. Af-cor'nbination as dened in claim 15, including afc'ovring wall removably attached to said casing 'and providing a space in which said pilot-supplypipe extends downward, said covering Wall separating said space from the air circulating in said circulating-air passage, and in which said pilot-guiding passage extends toward and terminates short of said covering wall a sufficient distance to permit said pilot-connected portion to move clear of said pilot-guiding passage and be disposed in the remaining space between the end of said passage and said casing to be movable from the Zone of the pilot-guiding passage when said covering wall is removed.

17. A combination as dened in claim 15, in which said casing provides a bottom wall, said pilot-guiding passage being adjacent said wall.

18. A combination as defined in claim 15, including a covering wall removably attached to said casing and providing a space in which said pilot-supply pipe extends downward, said covering wall separating said space from the air circulating in said circulating-air passage, and in which said casing provides a bottom wall, said pilot-guiding passage being adjacent said wall, and in which said pilot-guiding passage extends toward and terminates short of said covering wall, said bottom wall providing an opening extending from the end of said pilot-guiding passage and opening on the interior of said space provided by said covering wall, said opening provi-ding space for the vertical passage for said pilot-connected portion of said pilot-supply pipe when withdrawn from said pilot-guiding passage.

19. In a heating unit for installation in the floor of a building, said oor being disposed a distance above the ground suii'cient to receive the heating unit when lowered through an opening of the door, there being a fuel-supply pipe extending inwardly a short distance into the Zone through which said heating unit moves during lowering into installed position, said heating unit including in combination: an outer casing having an open top and being of such size as to be lowered through the opening of said licor, said outer casing providing a wall having an outwardly-facing substantially vertical passageway to receive the inwardly-extending portion of said fuel-supply pipe during installation of said outer casing; a combustion-chamber structure within said outer casing; a burner for burning fuel in said combustion-chamber structure; and pipe means extending upward from said burner to be connectible with said fuel-supply pipe.

20. In a heating unit for installation in the iioor of a building, said floor being disposed a distance above the ground sufficient to receive the heating unit when lowered through an opening of the floor, there being a fuel-supply pipe extending inwardly a short distance into the Zone through which said heating unit moves during lowering into installed position, said heating unit including in combination: an outer casing having an open top and being of such size as to be lowered through the opening of said floor, said outer casing including an upright wall having a vertical slot providing an open portion Vadapted to receive the inwardly-extending portion of said fuel-supply pipe when said casing is in installed position, said slot providing space for said inwardly-extending portion of said fuel-supply pipe during installation of said outer casing; a combustion-chamber structure within said outer casing; a burner for burning fuel in said combustion-chamber structure; and pipe means extending upward from said burner to be connectible with said fuel-supply pipe.

21. In a heating unit for installation in the floor of a building, said iioor being disposed a distance above the ground sufficient to receive lthe heating unit when lowered through an opening of the iioor, said heatingA unit including in combination: an outer casing having an open top and adapted for suspension in said opening to be disposed below said floor; a combustionchamber structure mounted within said outer casing and spaced therefrom to dene a circulating-air passage, said combustion-chamber structure providing a combustion chamber; a burner for burning fuel in said combustion chamber; means for conducting products of combustion from said combustion chamber; a pilot ttingv near the upper end of said outer casing; walls extending downwardly and inwardly to said combustion chamber and deilning a passageway substantially closed at its sides from communication with the air in said circulating-air passage, the upper and lower ends of said passageway being disposed respectively adjacent said pilot fitting and said combustion chamber; a pilot structure including a small pilot-supply pipe and a pilot .connected thereto; and means for removably mounting said pilot structure within said passageway in position to dispose said pilot in communication with said combustion chamber, said means including means for detachably connecting said pilot-supply pipe to said pilot fitting to permit upward withdrawal of the pilot structure from the heating unit without removal of the lf3 combustion-chamber structure from said outer casing.

22. In a heating unit for installation in the floor of a building, said floor being disposed a distance above the ground sufficient to receive the heating unit when lowered through an opening of the floor, there being a fuel-supply pipe immediately beneath said oor, said heating unit including in combination: an outer casing having an open top and being of such size as to be lowered through the opening of said oor; a combustion-chamber structure secured within said outer casing and spaced therefrom to define a circulating-air passage, said combustion-chamber structure providing a combustion chamber; a partition wall within said outer casing and providing sides extending to said outer casing and an intermediate portion spaced from said outer casing to dene a space having an upper end adjacent said fuel-supply pipe and a lower end horizontally opposite a portion of said combustion chamber; means for removably mount- 14 ing said partition wall within said outer casing, said means including inter-engaging means 0n said outer casing and said sides of said partition wall; and fuel-conducting piping connectable to said fuel-supply pipe and extending downwardly in said space to supply fuel to said combustion chamber.

JAMES STANLEY JOHNSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

